Photocatalyst material

Abstract

A photocatalyst material (1A) in accordance with an aspect of the present invention includes a core particle (2) and a shell layer (3) with which a whole surface of the core particle (2) is covered. The core particle (2) contains at least a tungsten oxide, and the shell layer (3) is constituted by a titanium oxide.

The invention claimed is: 
     
       1. A visible light response type photocatalyst material comprising:
 a core particle; and 
 a shell layer with which a whole surface of the core particle is fully covered, 
 the core particle containing at least a tungsten oxide, and 
 the shell layer being constituted by a titanium oxide, wherein 
 the visible light response type photocatalyst material undergoes photocatalytic activity when irradiated with visible light, 
 a weight proportion of the shell layer to the core particle is 0.4 or greater and 0.9 or less. 
 
     
     
       2. The visible light response type photocatalyst material as set forth in  claim 1 , wherein:
 the shell layer is constituted by a crystalline titanium oxide. 
 
     
     
       3. The visible light response type photocatalyst material as set forth in  claim 1 , wherein: a metal or a metal compound containing at least one of copper, platinum, palladium, iron, silver, gold, nickel, ruthenium, iridium, niobium, and molybdenum is provided on a surface of the shell layer. 
     
     
       4. The visible light response type photocatalyst material as set forth in  claim 3 , wherein: an amount of a metal contained in the metal or in the metal compound is 0.01 wt % or greater and 3 wt % or less with respect to the tungsten oxide contained in the core particle. 
     
     
       5. The visible light response type photocatalyst material as set forth in  claim 1 , wherein: the core particle contains a mixture of a tungsten oxide and a copper oxide. 
     
     
       6. The visible light response type photocatalyst material as set forth in  claim 5  wherein: an amount of the copper oxide contained in the core particle is greater than 0.01 wt % and less than 100 wt % with respect to the tungsten oxide contained in the core particle. 
     
     
       7. A method of producing a visible light response type photocatalyst material,
 said visible light response type photocatalyst material comprising:
 a core particle; and 
 a shell layer with which a whole surface of the core particle is fully covered, said method comprising: 
 growing, by adding a solution containing a titanium oxide precursor to a solution in which at least tungsten oxide particles each serving as the core particle are dispersed, a titanium oxide layer on a whole surface of at least one of the tungsten oxide particles, wherein 
 
 the visible light response type photocatalyst material undergoes photocatalytic activity when irradiated with visible light, 
 a weight proportion of the shell layer to the core particle is 0.4 or greater and 0.9 or less.